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Just Keep Prompting: VLM Epistemic Stability Under Pressure

By James Trappett · 18 July 2026

5 min read

Most multimodal benchmarks evaluate models on a single question, a single visual input, and a single answer. That design misses something important: real users ask follow-up questions, express doubt, and push back. A model that answers correctly once may still be unreliable if it abandons a visually grounded answer the moment a user says "are you sure?" This is the problem that Just Keep Prompting (JKP) sets out to quantify.

The paper sits at the intersection of two active research threads: multimodal grounding and sycophancy in aligned language models. The sycophancy literature has established that RLHF and DPO training can make models overly deferential to user sentiment, causing them to revise correct answers after pushback even when no new information is provided. JKP asks whether the same dynamic appears in video-language reasoning, where the model has access to objective perceptual evidence that should, in principle, anchor its answers.

The JKP Framework

The experimental design is straightforward and well-motivated. Each evaluation instance consists of a video clip, a multiple-choice question, and a ground-truth answer drawn from the STAR benchmark, a situated video reasoning dataset covering four question types: Interaction, Sequence, Prediction, and Feasibility. The model first answers at Turn 0, then receives up to ten follow-up prompts over the same video-question pair without any new visual information being introduced.

Three prompting strategies apply pressure in qualitatively different ways:

Models are required to return a structured response at each turn: an answer letter, a self-reported confidence score from 0 to 100, and a short rationale. This allows trajectory-level analysis across accuracy, confidence, and flip behaviour simultaneously. The evaluation covers GPT-4o, Gemini 2.5 Pro, and Qwen3-VL-30B across 720 multi-turn runs.

Key Findings

The headline result is that aggregate accuracy barely moves from Turn 0 to Turn 10. That stability is misleading. Trajectory-level analysis reveals substantial churn underneath the aggregate: some initially wrong answers recover, some initially correct answers regress, and many runs show repeated answer flipping. The paper's central claim is that repeated prompting acts as a destabiliser rather than a reliable reasoning aid, and the evidence supports that claim clearly.

Model-level differences are the most striking finding:

Category-level results add nuance. The Feasibility category, which asks what actions are physically or situationally possible, starts at only 23.3% accuracy and produces 2.62 flips per run on average. Repeated prompting does recover some wrong answers here, but those recoveries are accompanied by high oscillation rates and weak durability. The paper is careful not to interpret the small net improvement in Feasibility as evidence that prompting helps; the same destabilisation that occasionally recovers a wrong answer also degrades correct ones. The Interaction category, the easiest, shows the clearest anti-helpful pattern: models start near ceiling and have more room to fall than to rise.

Methodological Strengths and Limitations

The design choice to hold the visual input fixed across all turns is the right one for isolating conversational pressure effects. It rules out the confound of new information and makes answer changes interpretable as pressure responses rather than genuine updates. Using STAR rather than a static image benchmark is also well-motivated; video reasoning tasks require tracking temporal structure and physical affordances, which should in principle give the model richer grounding to draw on when resisting pressure.

That said, several limitations deserve acknowledgement. The sample is a subset of STAR, and the paper does not fully specify how that subset was selected or whether it is representative of the full benchmark distribution. The confidence scores are self-reported by the models and may not reflect calibrated uncertainty; treating them as ground truth for calibration analysis requires some caution. The three prompting strategies, while well-chosen, do not exhaust the space of conversational pressure. A user who provides a plausible-sounding but incorrect alternative answer, for example, would constitute a qualitatively different challenge not covered here.

The paper also does not attempt any intervention. It characterises the problem carefully but does not test whether instruction-level prompting, chain-of-thought grounding, or post-hoc consistency checks can mitigate the instability. That is a reasonable scope decision for a diagnostic paper, but it leaves the practical question open.

Implications for Evaluation and Deployment

The framing of multi-turn evaluation as a "pressure-response assay" is the paper's most useful conceptual contribution. The three model profiles identified, stubbornness, inertia, and compliance, map onto qualitatively different deployment risks. A stubbornly overconfident model is dangerous in high-stakes settings where a user might reasonably expect the model to update. A compliant model is dangerous in settings where users may inadvertently or deliberately push the model away from correct answers. Neither profile is obviously preferable in all contexts, which suggests that deployment decisions should account for the specific interaction pattern expected.

The finding that Socratic interrogation is more destabilising than explicit negation for GPT-4o is counterintuitive and worth further investigation. One interpretation is that "No, that is incorrect" is a clear enough signal that the model can process it as adversarial and resist, while repeated "are you sure?" prompts are ambiguous enough to be interpreted as genuine epistemic concern, triggering more compliance. If that interpretation is correct, it has implications for how alignment training handles ambiguous social signals.

For practitioners building VLM-powered applications, the practical takeaway is that single-turn accuracy is an insufficient deployment criterion when the intended use involves multi-turn interaction. A model scoring 75% at Turn 0 but flipping answers in 40% of runs under mild conversational pressure is not a 75% model in practice. JKP provides a concrete framework for measuring that gap, and the leaderboard format suggests the authors intend it to become a standard evaluation tool. Whether the community adopts it will depend on how well the benchmark scales to larger and more diverse video datasets.

The full paper is available at arXiv:2607.14099.

Vision-Language ModelsSycophancyMulti-Turn EvaluationLLM RobustnessVideo Reasoning

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